GlassFish Server Modular Architecture and Add-On Components

GlassFish Server has a modular architecture in which the features of GlassFish Server are
provided by a consistent set of components that interact with each other.
Each component provides a small set of functionally related features.

The modular architecture of GlassFish Server enables users to download
and install only the components that are required for the applications that
are being deployed. As a result, start-up times, memory consumption, and disk
space requirements are all minimized.

The modular architecture of GlassFish Server enables you to extend the
basic functionality of GlassFish Server by developing add-on components. An add-on component is an encapsulated definition of reusable code
that has the following characteristics:

The component provides a set of Java classes.

The component offers services and public interfaces.

The component implements the public interfaces with a set
of private classes.

The component depends on other components.

Add-on components that you develop interact with GlassFish Server in the
same way as components that are supplied in GlassFish Server distributions.